Apparatus and method for stacking rolls of pressure sensitive tape

ABSTRACT

A stacking and interleafing device for rolls of pressure sensitive adhesive tape has an inclined table adapted to hold a row of the rolls carried in a spaced relationship on a mandrel. The table supports a plurality of upright, parallel plates that separate the adjacent rolls. The plates maintain the rolls in a spaced apart relationship as the mandrel is drawn clear of the rolls and as they advance down the incline. An escapement mechanism mounted over the table successively transfers one row of stripped rolls from a storage portion of the table to a feeder portion of the table subtended by a movable drop-off mechanism. Translation of the drop-off mechanism gravity feeds the rolls, one at a time, and without contact between the rolls, to a conveyor system. A reciprocating shuttle plate receives the rolls from the conveyor system and successively carries each roll to a mandrel mounted on a rotatable stack forming arm. As the shuttle returns to receive another roll, the preceding roll drops onto the mandrel. Suction ports located on the underside of the shuttle strips a release liner from a supply magazine and carries it with the roll to the stacking mandrel. When the shuttle positions the roll and the release liner over the mandrel, a valve arrangement releases the vacuum and the release liner drops onto the mandrel thereby interleafing with the rolls as they are stacked. When a predetermined number of rolls are stacked and interleafed, the rotatable arm indexes to bring an empty mandrel in the stack forming or &#34;load&#34; position. At the same time, the stacked mandrel is carried to an &#34;unload&#34; position. A fork lift elevator and associated stack handling devices remove the stack from the mandrel in the unload position and convey it to a packer.

This is a division, of application Ser. No. 622,155, filed Oct. 14,1975, now U.S. Pat. No. 4,030,619.

BACKGROUND OF THE INVENTION

This invention relates in general to stacking and packaging devices andmethods, and more specifically to a novel apparatus and method forautomatically stacking rolls of pressure sensitive adhesive tape andinterleafing them with a release liner so that the rolls will not adhereto one another when packaged.

In the manufacture of rolls of pressure sensitive adhesive tape, it iswell known in the art to slit a web of adhesive coated material intonumberous strips of lesser width. The strips are, simultaneous withslitting, wound into rolls of some suitable length of tape, each rollbeing formed on a separate core carried on a mandrel. As the sides ofthe rolls may themselves be tacky due to the adhesive which exudes fromthe roll convolutions, it is common to employ two parallel, spaced apartmandrels as described in U.S. Pat. No. 3,127,123 to Bowker et al.,issued Mar. 31, 1964. Adjacent strips are directed from the slitter todifferent mandrels, thereby spacing the rolls of adhesive tape from oneanother on each of the mandrels by a distance equal to the width of asingle roll. Thus, in the event adhesive is present on the face of theroll, the adhesive faces will not be in contact with one another.

The rolls are then removed from each mandrel and stacked together insome desired number in preparation for packaging. The standard techniqueis simply to slide or to push the rolls off the mandrel. This results inthe rolls coming into face-to-face contact. Where there is an exudate ofadhesive, the rolls adhere strongly to one another. As a result, therolls must then be pried or pulled apart. Heretofore, this separationhas been done by hand, usually with the aid of a knife or similar tool.Once separated, the rolls are then stacked by hand and interleafed withpaper. These release papers are placed between the adjacent rolls in thestack to prevent them from again adhering to one another during storagein preparation for marketing.

These manual roll separation and stack formation processes have a majordisadvantage in that they are extremely slow. In the overall productionprocess, these steps are frequently the limiting factors on productionspeed. Further, the rolls are frequently damaged when they are priedapart. A common problem is "dishing" or "telescoping" where the innerconvolutions of the rolls are pulled out of an overlying alignment withthe outer convolutions. This problem is particularly acute in theproduction of rolls of pressure sensitive tape having a width of 1/4inch or less. Still further, the use of sharp, hand-held knives andtools needed for separating adjacent rolls adhered together, presents aclear safety hazard.

It is therefore a principal object of this invention to provide anapparatus and method for automatically stacking and interleafing rollsof pressure sensitive adhesive tape initially carried in a spacedrelationship on a mandrel whereby the rolls are prevented from adheringto one another.

Another object is to provide a stacking and interleafing apparatus andmethod that substantially increases production speed and reduces themanufacturing cost of pressure sensitive adhesive tape.

SUMMARY OF THE INVENTION

This invention provides an inclined table adapted to receive a mandrelcarrying a row of spaced apart rolls of pressure sensitive adhesivetape. The table supports a plurality of upright, parallel, spaced apartplates aligned so that they are interposed between adjacent rollscarried on the mandrel. When the mandrel is extracted by a pullingmotion transverse to the plates, the plates maintain the rolls in aspaced relationship. Once the rolls are stripped from the mandrel, theyadvance down the divider table in the channels defined by the "divider"plates until restrained by an escapement mechanism mounted over thetable. Preferably the table has the capacity to store more than one rowof rolls between the mandrel stripping area and the escapement, andtherefore a row of stripped rolls may come to rest against thepreviously stripped row.

The escapement repeatedly transfers a single row of rolls to a feederportion of the inclined stripper table extending along its lower edgeand subtended by a movable dropoff mechanism or member. A translation ofthe mechanism in a direction substantially transverse to that of theplates allows the rolls to drop one at a time, and without contact withan adjacent roll, to an underlying conveyor system that transports therolls to a stack forming apparatus.

A stack of the rolls is formed on a "load" mandrel mounted on arotatable arm. A reciprocating shuttle plate receives the rolls from theconveyor system and repeatedly carries each roll to a position over theload mandrel. As the shuttle returns to receive the following roll fromthe conveyor system, a pivoted retainer carried on the upper end of themandrel holds the roll over the mandrel until it clears the shuttle anddrops onto the arm or a previously stacked roll. Suction ports formed onthe underside of the shuttle strip a release liner from a supplymagazine and carry it along with an overlying roll to the load mandrel.When the liner is positioned over the load mandrel, a valve release thevacuum supply to the suction ports and allows the release liner to droponto the load mandrel and interleaf the stacked rolls.

When the stack reaches a predetermined number of rolls, the rotatablearm indexes to introduce an empty mandrel to the load position andsimultaneously carries a stacked mandrel to an unload position. A forkedelevator, acting in phase with a sweep arm and an off-bear conveyor,transfers the stack from the "unload" mandrel to a packer.

This and other features and advantages of this invention will be morefully understood from the following detailed description to be read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified and exaggerated perspective view of a preferredembodiment of a stacking and interleafing apparatus constructedaccording to the invention;

FIG. 2 is a top plan view of the apparatus shown in FIG. 1;

FIG. 3 is a view in front elevation of the apparatus shown in FIG. 1;

FIG. 4 is an enlarged view in front elevation of the drop-off mechanismshown in FIG. 1;

FIG. 5 is a view in side elevation, with portions broken away, of theapparatus shown in FIG. 1;

FIG. 6 is a view corresponding to FIG. 5 showing the escapement pivotingto advance a row of rolls; and

FIG. 7 is a view corresponding to FIG. 6 showing the escapementcompletely pivoted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 2, a mandrel 12 carries a row of rolls 14of pressure sensitive adhesive tape that are spaced along the axis ofthe mandrel a distance equal to the width of a single roll. This is doneso that adjacent rolls will not adhere to one another as the side facesof each roll typically carry adhesive material which has exuded from theroll convolutions.

The mandrel 12 is placed in an inclined table 16 having a generallyrectangular shape defined by a lower frame member 18, an upper framemember 20 that is substantially parallel to the lower member 18, and apair of substantially parallel side frame members 22 and 24 that extendbetween the members 18 and 20 along the axis of inclination of thetable. The orientation of the mandrel 12 is generally transverse to theaxis of inclination of the table. The table has a floor or base 26 thatextends to the frame members 20, 22 and 24, but is spaced from the lowermember 18. This open space 28 (FIG. 5), is defined by the frame member18, the free edge of the base 26, and the portion of the side members 22and 24 that extend between the member 18 and the free edge. The space 28extends the full width of the table and extends along the axis ofinclination for a distance at least equal to the maximum diameter of aroll 14 to allow the rolls to drop out of the table in a mannerdescribed in greater detail below.

The frame members 18 and 20 are long enough to include all of the rolls14 carried on the mandrel 12 between the side frame members 22 and 24.The side members 22 and 24 are preferably long enough for the table 16to hold at least four rows of rolls with the rolls resting on edge onthe base 26 and adjacent rows in edge-to-edge tangential contact. Theside members 22 and 24 each have an open, upwardly facing slot 30adapted to hold an end of the mandrel 12 while removing the rollstherefrom. The slots 30 are spaced from the upper frame member 20 asufficient distance to allow a small clearance between the rolls and themember 20 when the mandrel is cradled in the slots.

Supported by the table 16 are a plurality of substantially flat, uprightplates or dividers 32, each having a generally rectangular shape, whichdivide the table into a number of inclined compartments depending on thenumber of rolls on the mandrel. The plates 32 extend from the lowerframe 18 to the upper frame 20 with the ends of each plate being held ina suitable locating slot 33 formed on the inwardly facing surfaces ofthe members 18 and 20 and the upper surface of the base 26. Each plate32 is substantially perpendicular to the members 18 and 22 and to base26 and extends substantially along the axis of inclination of the table.The locating slots 33 are spaced and aligned so that the plates 32 arein a mutually parallel and spaced apart relationship with at least oneplate 32 interposed between the adjacent faces of each roll pair carriedon the mandrel 12. The upwardly facing edge of each plate 32 also hasformed therein an open slot 32a similar to the slot 30 and adapted toreceive the mandrel 12 when it is located in the slots 30. The plates32, as well as the table 16, may be constructed from any suitablestructural material such as metal, wood or plastic, but stainless steelor aluminum are preferred.

When the mandrel 12 rests in the slots 30, the plates or dividers 32restrain the rolls from being drawin into face-to-face contact as themandrel is drawn clear of the rolls by pulling or pushing it along itslongitudinal axis. As the mandrel clears the core of each roll, the rollis free to advance down the inclined table under the influence ofgravity towards the lower frame member 18. During this advance, theplates 32 guide the rolls and support them in the "on-edge" orientationwith respect to base 26. It should be noted that although the angle ofinclination of the table 16 (the angle between the floor 26 and thehorizontal) is not critical, it should be sufficient to overcome theadhesive forces between the rolls and the table and/or the plates. Anangle of inclination of approximately 10 degrees has been found to besufficient in most instances.

An escapement mechanism 34 mounted over the table 16 divides the tableinto an upper storage portion 16a subtended by the base 26, and a lowerfeeder portion 16b, corresponding to the open space 28, defined by theframe member 18, the lower portions of the side members 22 and 24 andthe free edge of the base 26. With particular reference to FIGS. 5-7,the escapement 34 has a pair of parallel, spaced apart stop rods 36 and38 carried between a pair of rocker arms 40 mounted on the table on apivot pin 42. The lower stop rod 36 is positioned to restrain thedownhill advance of the lowermost row of rolls (and indirectly anysubsequently stripped rows of rolls in the portion 16a) when theescapement is in its initial blocking position shown in FIG. 5.Periodically a hydraulic or air cylinder 44 rapidly pivots theescapement mechanism about the pin 42 from the blocking position,through the intermediate position shown in FIG. 6, to a row feedposition shown in FIG. 7. In the feed position, the rear stop rod 38restrains all of the rows of rolls in the storage portion 16a against adownward advance while the lowermost row of rolls, previously in contactwith the stop rod 36, advances into the feeder portion 16b of the table.The rapidity of the pivoting movement and the position of the stop rod38 on the rocker arms 40 are selected to ensure that the rod 38 does notcrush or "football" the rods as it contacts them.

Since it was observed that exuding adhesive from a roll couldoccasionally prevent one or more rolls from advancing promptly intoportion 16b of the table when the escapement 34 pivots, there isprovided a blade 46, mounted to pivot about a rod 48 supported betweenthe rocker arms 40, that sweeps or kicks the lowermost row of rolls intothe feed area 16b. The sweeping motion is generated by curved portion46a of the blade 46 camming against a fixed stop 50 secured to the sidemember 22 (compare FIGS. 6 and 7). The free edge 46b of the blade ispositioned to drive the lowermost roll of rows in the table portion 16ainto the portion 16b as indicated by the arrow 52 in FIG. 7. When theescapement pivots back to its initial position, a torsion spring 53, oran equivalent, pivots the blade 46 to its initial position. At the sametime the rolls previously held against the rod 38 advance downwardlyuntil restrained by the stop rod 36.

The feeder portion 16b is subtended by a movable drop-off mechanism ormember 54 which can be best understood with reference to FIGS. 4-7. Thedrop-off mechanism 54 moves between a forward position in which itunderlies all of the table portion 16b and a rear position in which itis completely clear of the table portion 16b. Movement of the drop-offmechanism between these positions, in a left to right direction as seenin FIG. 1, is coordinated with the action of the escapement mechanism 34so that each time a row of rolls is transferred to the table portion16b, the drop-off mechanism is in the forward position and the row ofrolls are supported by the drop-off mechanism.

The drop-off mechanism 54 comprises a flat-top conveyor chain 56 havinga series of links hinged together. The chain 56 tracks in a pair ofgrooved ways 57 (FIGS. 5-7) that engage the ends of each link over theregion proximate the feeder portion 16b of the table. A gear 58, poweredby a reversible hydraulic motor (not shown), propels the chain 56between the forward and rear positions. The forward end of the chain 56(the left end as illustrated) supports an idler roller 62 oriented in adirection substantially transverse to the direction of movement of thechain. The chain also supports a spring loaded reel 64. A flexible strip66 is looped over the idler 62 with one end wound on the spring loadedroll 64 and the other end secured to a fixed bar 68. The belt 66 ispositioned so that the rolls in the feeder portion 16b rest on the belt66 which remains stationary under each roll as the chain 56 translates,rather than making contact with the chain itself which moves relative tothe rolls.

As the chain 56 moves from the forward position to the rear position, itsuccessively clears the rolls resting on the belt 66 and these each inturn fall in a spaced relationship onto a conveyor belt 70 thatunderlies both the table portion 16b and the drop-off mechanism 54. Thespeed of movement of the drop-off mechanism relative to that of theconveyor 70 is such that the rolls are fed from the table portion 16b tothe conveyor without contact between any of the rolls. It should benoted that during the translation of the drop-off mechanism, the belt 66winds onto the roller 64 so that there is no relative movement betweenthe rolls and the belt. As the rolls fall, they strike a lip 72 which issuspended from the chain 56. The lip 72 has an end portion 72a angled ina direction opposite to the direction of movement of the escapementmechanism as it feeds the rolls, which imparts a stable horizontalorientation to the rolls as they land on the conveyor belt 70. It shouldbe noted that the rolls carried on the conveyor 70 move in a directionopposite to that of the drop-off mechanism 54 as it moves from itsfoward to rear position.

As can be best seen in FIGS. 1 and 2, the conveyor belt 70 transfers therolls to a horseshoe shaped turn-around 74 having an initial series ofcylindrical rolls 76, a series of tapered rolls 78 that carry the rollsaround the bottom of the horseshoe, and a final leg preferably formed bya set of parallel polyurethane bands 80 carried between a pair ofcylindrical rolls 82. The rolls 76, 78 and 82 are all driven, preferablyat rotational speeds which convey the rolls at a generally constantlinear speed. It should be noted that the ends of the horseshoeturn-around are at different levels, primarily to accommodate thecomponents with varying vertical dimensions, while placing all of theapparatus at a level that is conveniently accessible to an operator ormaintenance personnel. It should be also noted that the rolls and thebands 80 forming the turn-around 74 are inclined and/or slopedtransversely, a sufficient degree to avoid having any part of a rolllift off the turn-around a sufficient distance to allow a preceding orfollowing roll to jam under the lifted portion.

As the rolls leave the horseshoe turn-around 74, they slide over an endplate 84 and come to rest on an upward facing surface of a shuttle plate86. The speed at which the rolls leave the horseshoe turn-around can beadjusted to carry each roll onto the shuttle, or, more typically, therolls back up, in tangential, edge-to-edge contact, from the shuttle 86,onto the turn-around 74 so that the turn-around continuously urges therolls onto the shuttle. Each roll is guided along a fence 87 onto theshuttle until it strikes a microswitch actuator 88 located at the freeend of the fence 87 facing the horseshoe turn-around. When the rolltrips the actuator arm 88, it is automatically properly located on theshuttle 86.

When a roll trips the actuating actuator 88, the microswitch 90energizes a hydraulic motor 92. Rotation of the motor shaft 93 and theconnected wheel 94, acting through an eccentrically mounted crank arm96, pivots the shuttle support arm 98 about an upright support shaft100. A 180° rotation of the wheel 94 drives the shuttle from its initialroll receiving limit position (FIGS. 1 and 2), along a curved path inthe direction of the arrow 102 (FIG. 1), to a stack forming limitposition directly over an upright stack forming or "load" mandrel 104aof a rotatable arm 106. The arm 106 periodically rotates or indexesthrough 180° increments that carry the mandrel 104a to an "unload"position. A mandrel 104b, initially in the "unload" position issimultaneously carried into the "load" position.

The leading edge of the shuttle plate 86 has an open slot 86a whichextends from the "leading" edge of the shuttle to a point beyond thecore opening of the roll 14 carried on the shuttle plate. Because of theopen slot 86a, as the shuttle carries the roll over the mandrel, theroll depresses the normally raised end 108a of a pivoted retainer member108 mounted at the upper end of the mandrel 104a. When the central coreopening of the roll 14 is positioned over the retainer member 108, theshuttle 86 has reached its extreme forward position and the end 108areturns to its normal raised position within the core. Continuedrotation of the motor 92 and the wheel 94 then reverses the direction ofthe motion of the shuttle 86 bringing it back to its initial limitposition to receive the following roll 14 from the turn-around 74. Asthe shuttle plate returns, the raised portion 108a prevents the roll 14from also returning. When the shuttle plate clears the roll, the rolldrops onto the mandrel 104a and is thus stacked. When the shuttle 86 isin its forward position (over the mandrel), a roll will be positionedagainst the fence 87 on the trailing surface of the shuttle 86. When theshuttle 86 returns to its back position the roll will then be inposition for delivery to the mandrel.

During each movement from the initial roll receiving position to themandrel 104a or 104b, the reciprocating shuttle plate 86 also carries arelease liner 110 shaped in the form of an annulus. A release linermagazine 112 is located directly below the shuttle in its initial rollreceiving position. The shuttle strips the top release annulus from themagazine and carries it to the load mandrel by means of suction ports114 formed on the under side of the shuttle 86. A vacuum pump 116generates the suction. The pump 116 is connected to the ports 114through a vacuum line 117. The vacuum line 117 contains a valve 118which is switched between an open and closed position by an operatingarm 118a which is positioned to strike the fixed stops 120 and 122. Asthe shuttle returns to the roll receiving limit position, the stop 120opens the valve 118 causing the ports 114 to stip the top release liner110 from the magazine 112. The suction ports 114 grip the release lineruntil the stop 122, on forward movement of the shuttle, closes the valve118 and opens the vacuum bleed causing the release liner to fall ontothe load mandrel. As the supply of release liners in the magazine beginsto diminish, suitable sensing means such as a pressure switch activatesa hydraulic motor 124 which raises the entire supply of liners held inthe magazine 112 so that the topmost liner is proximate the ports 114and readily stripped from the magazine. A limit switch is also providedwhich shuts down the entire apparatus whenever the release liner supplyneeds to be replenished.

The shuttle 86 will continue to stack roll and release liner pairs onthe load mandrel until the stack formed on the mandrel reaches apredetermined number of rolls. In the illustrated embodiment of theinvention, as each roll is carried over the load mandrel, it strikes alimit switch 126 which provides a signal to suitable counting device(not shown). When the count reaches a preselected number, correspondingto the desired number of rolls in each stack, a motor 127 is energizedto index the rotatable arm and mandrels 106 through 180 degrees and themandrels 104a and 104b exchange positions. While the arm 106 indexes, abrief delay is preferably introduced into the activation control of theroll feeding and stack forming mechanisms described hereinabove.

With the stacked mandrel 104a in the unload position, a forked elevator128 is activated to lift the stack from the arm to the level of anoff-bear conveyor belt 130 whose top run moves in the directionindicated by the arrow 132 (FIGS. 1 and 2). When the elevator 128reaches its fully raised position, a sweep arm 134 activated by an aircylinder 136 draws the stack over an idler roller 138 (FIGS. 2 and 3)and onto the conveyor 130. The idler roller 138 stabilizes the stackduring the transfer. The off-bear conveyor 130, which may operatecontinuously or intermittently, carries a stack 140 (FIGS. 1-3) ofrolls, or a number of stacks of rolls, to a packer who usually enclosesthe stack in a plastic bag and places it in a shipping carton.

In a typical production operation, a large supply web of adhesive coatedmaterial 55 inches in width is slit into narrow strips, 1/4 inch to 2inches in width. The narrow strips are then wound on cores carried on amandrel 12, with alternate strips being directed to another mandrel. Therolls on each mandrel are therefore spaced by the width of the tapebeing wound. Typical dimensions for a roll of tape are a core insidediameter of three inches and an outer diameter of 4 to 61/8 inches. Whenthe rolls are wound, each mandrel 12 is transferred in turn to theinclined table 16 and placed in the slots 30 and 32a. At least onedivider plate 32 separates each adjacent pair of rolls carried on themandrel. The plates 32 are adjustably spaced by varying their numberand/or location to accommodate rolls of varying width. For this purpose,the locating slots 33 are spaced at convenient intervals, such as every1/4 inch. To strip the rolls, the mandrel is simply pulled or pushedalong its longitudinal axis. As the mandrel successively clears eachroll, they advance down the table until they strike the escapement stoprod 36 or a previously stripped roll. The stripping process can berepeated indefinitely as long as there is room in the table portion 16afor another row of rolls.

Automatic mechanical operations on the rolls begin with the pivoting ofthe escapement mechanism 34 to feed the lowermost row of rolls in thestorage portion 16a to the feeder portion 16b. The row of rolls thus fedcomes to rest on the flexible belt 66 of the drop-off mechanism 54 whichis initially in its forward limit position. The drop-off mechanism thenbegins to move to its rear position which successively gravity feeds therolls, one at a time and without contact between any of the rolls, tothe underlying conveyor 70. After all of the rolls in the feeder portion16b have been fed to the conveyor 70, the drop-off mehcanism quicklyreturns to its forward limit position and the escapement again pivots torefill the feeder portion with another row of rolls. The return speed ofthe drop-off mechanism, however, does not exceed that of the conveyor toprevent the lip 72 from pushing together the rolls remaining on theconveyor.

The conveyor 70 and the turn-around 74 carry the rolls to the shuttleplate 86. Each roll 14 advances onto the shuttle guided by the fence 87and the actuator 88, until it trips the microswitch. This initiates areciprocation of the shuttle to a forward limit point directly over oneof the stack forming mandrels 104a or 104b and back to the initialposition. As the shuttle 86 carries each roll 14 to a stack formingmandrel, it also carries release liner 110 which drops over the stackforming mandrel to interleaf the adjacent rolls in the stack. The firstrelease liner is automatically deleted from each stack of rolls beingformed on the mandrel. This is done because since otherwise it would belost during stack removal. When the stack contains a predeterminednumber of rolls, the mandrels 104a and 104b exchange positions tointroduce an empty mandrel to the stack forming or load position andplace the stacked mandrel in a stack removal or unload position. Thestack unloading operation begins with the fork elevator 128 raising thestack clear of the mandrel. The sweep arm 134 then transfers the stackto the off-bear conveyor 130. The elevator then lowers to its originalposition. During the stack removal operation, the shuttle continues tostack and interleaf rolls on the mandrel in the load position. Typicallythe apparatus described hereinabove can stack and interleaf rolls ofpressure sensitive tape, without contact between the faces of the rolls,at a rate of 1 to 2 rolls per second.

Although the above detailed description has been directed to thepreferred embodiment of the invention, various alternative arrangementscan be employed to perform the operations described above, and sucharrangements are inteded to fall within the scope of the invention. Forexample, the table 16 can have a two row capacity, a mandrel strippingposition and a feed position, or only a one row capacity, with thestripping function performed directly in the feeding area with the rollsresting on the drop-off mechanism. These arrangements have the obviousdisadvantage of a slower rate of operation. It is also contemplated thatthe plates can assume a wide variety of shapes provided that theyperform the necessary separation function. Further, it is contemplatedthat the plates can be carried by a supporting structure other than thetable 16, provided they interpose the adjacent rolls held on the table.

The advancement of the rolls in the table 16 can be accomplished bynon-gravitational means such as underlying conveyor belts or compressedair jets, and in that event the table 16 may not require an inclinationfrom the horizontal. Further, it is contemplated that those skilled inthe art can devise various alternative escapement devices to control themovement of the rolls on the table.

Similarly the drop-off mechanism can assume a variety of forms. In amore highly simplified form, the drop-off mechanism can consist of asingle sheet of a flexible structural material such as stainless steelwith the rolls resting directly on the sheet. This arrangement, however,has the disadvantage of drawing the rolls sideways, in the direction ofmovement of the sheet, which can cause the rolls to "hang up" in thefeeder portion due to and adhesion between the roll face and the plate32.

The stack forming mechanisms can also assume a variety of forms. Onearrangement involves a stack forming mandrel with a plurality ofradially extending stack forming arms which rotate in a vertical plane,in succession, through a roll load position and a stack unload position.Using this type of stack forming mandrel, the rolls can be tossed ontothe load arm by a flipper plate which serially receives the rolls fromthe conveyor system. A photorelay triggered by a roll seating on theflipper plate has been found suitable for controlling the movement ofthe flipper plate. In contrast to the simultaneous interleafingdescribed hereinabove, the release liners can be fed alternately withthe flipper plate or its equivalent. One arrangement employs a roller tostrip the release liners from the magazine and direct them through achute to the load arm. Another arrangement utilizes a vacuum system withsuction pick-up heads carried on the ends of a plurality of radiallyextending arms. The heads successively rotate to a supply magazine wherethey strip away a release liner, and a position over the stack formingor load arm where they release the liner. It should be noted that therotatable arm 106 can carry more than two mandrels 104 provided that thenecessary alterations are made in the location of the neighboring and/orassociated mechanisms, and the mandrel index angle is correspondinglyadjusted.

These and other modifications will become apparent to those skilled inthe art from the foregoing description and accompanying drawings. Suchmodifications are intended to fall within the scope of the appendedclaims:

What is claimed is:
 1. In the manufacture of rolls of pressure sensitivetape wherein a plurality of said rolls are carried on a mandrel in aspaced relationship, the method of stacking said rolls comprising incombination,interposing divider members between adjacent rolls on themandrel, drawing the mandrel clear of the rolls, storing rolls thuscleared in said spaced relationship, periodically transferring the rollsthus stored to a feeder area, serially removing the rolls from saidfeeder area without contact between the faces of any of the rolls,stacking the rolls thus removed, placing a release sheet between theadjacent faces of the rolls as they are stacked, and removing the stackwhen it has a predetermined number of rolls.
 2. A roll stacking methodaccording to claim 1 in which said serial removal step comprises gravityfeeding the rolls by translating a member that supports a row of saidrolls from a position in which it supports all of the rolls in the row,to a position in which it supports none of the rolls.
 3. A roll stackingmethod according to claim 2 in which said serial removal occurs at arate of approximately one roll per second.
 4. A method of handling rollsof pressure sensitive tape where the rolls are carried in a spacedrelation on a mandrel passing through apertured portions of said rollsand supported by a support means comprising the steps ofsupporting saidmandrel in a generally horizontal orientation, withdrawing said mandrelfrom said apertured roll portions, maintaining said spaced relationbetween said rolls as said mandrel is withdrawn, gravity feeding saidrolls sequentially from said support means following said mandrelwithdrawal and said separation maintenance without contact between saidrolls, and conveying said sequentially fed rolls in a mutually spacedrelation from said support means.
 5. The method of claim 4 furthercomprising the step of forming an interleafed stack of said rolls.